Chromeless window - load page

Hi, i’m very new to flashing and action scripting alike. so it’s your help i need. i am implementing a chromeless pop-up window, which i have working from the onPress event as such

 
chromelessButton.onPress = function()
{
getURL("javascript:myChromeless.openChromeless()"); 
}

What do i need to do to take this one step further and assign it to onLoad (or whatever)
as i have tried

chromelessButton.onLoad = function()
{
getURL("javascript:myChromeless.openChromeless()"); 
}

As well as assigning the createChromeless() from the javascript
But nothing loads at all either way.
Thanks
for any help

Dan